Hey there thank you for posting in the Lucid community! Our sincere apologies for the delayed response on this thread - I wanted to follow up in case this answer may still be useful to you and to provide a solution for other users who see this thread in the future.

Unfortunately the shape you are looking for is not currently available in Lucidchart. However we're always looking for ways to improve Lucidchart and your feedback is the best way for us to do that. I've gone ahead and submitted your idea to our product team on your behalf and it will be taken into consideration when prioritizing improvements to the product. Please note that in the meantime you can create advanced custom shapes. To learn more check out our Modify Format and Style Shapes article. 

For anyone else with a similar request: please submit your feedback using this feature request form in order to voice additional support to our development team. We would also love to hear additional detail about your use case or see an example of what you're hoping to achieve in the thread below. Additionally if you've discovered a workaround to achieve something similar in the meantime we'd love to hear about it!Thanks for your request!